On Monday, Ford unveiled a new F-150 with a body built almost entirely out of aluminum. The lighter material shaves as much as 700 pounds off the 5,000-pound truck, a revolutionary change for a vehicle known for its heft and an industry still heavily reliant on steel.

The change is Ford’s response to small-business owners’ desire for a more fuel-efficient and nimble truck — and stricter government requirements on fuel economy. And it sprang from a challenge by Ford’s chief executive to move beyond the traditional design for a full-size pickup.

‘‘You’re either moving ahead and you’re improving and you’re making it more valuable and more useful to the customer or you’re not,’’ chief executive Alan Mulally said in a recent interview.

Ninety-seven percent of the body of the 2015 F-150 is aluminum, the most extensive use of aluminum ever in a truck.

And this is not just any truck. F-Series trucks — which include the F-150 and heavier duty models like the F-250 — have been the best-selling vehicles in the United States for the last 32 years; last year, Ford sold an F-Series every 41 seconds.

The key question for Ford, and the people who sell its trucks, is: Will customers embrace such a radical change?

Dealers who have seen the new F-150 say they expect to encounter some skepticism, but the change had to be made.

‘‘We’re aggressive, stretching the envelope,’’ said Sam Pack, owner of four Ford dealerships in the Dallas-Fort Worth area. ‘‘I think you have to do that. If you don’t, then you get into that predicament of being a ‘me too’ vehicle.’’

Still, it is a big risk. Ford makes an estimated $10,000 profit on every F-Series truck it sells, making trucks a $7.6 billion profit center in the United States alone last year.